海底热液硫化物中金属、非金属和稀有气体同位素组成的关系及其地质意义  

The Relationship Between Isotopic Compositions of Metals,Non-Metal,and Rare Gases in Seafloor Hydrothermal Sulfides and Its Geological Significances

作　　者：曾志刚[1,2,3] Zeng Zhigang(Institute of Oceanology/Key Laboratory of Marine Geology and Environment,Chinese Academy of Sciences,Qingdao 266071,Shandong,China;Laboratory for Marine Mineral Resources,Laoshan Laboratory,Qingdao 266061,Shandong,China;College of Marine Sciences,University of Chinese Academy of Sciences,Qingdao 266400,Shandong,China)

机构地区：[1]中国科学院海洋研究所/中国科学院海洋地质与环境重点实验室,山东青岛266071 [2]崂山实验室海洋矿产资源功能实验室,山东青岛266061 [3]中国科学院大学海洋学院,山东青岛266400

出　　处：《吉林大学学报（地球科学版）》2024年第1期1-19,共19页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(42330409,42221005,91958213);中国科学院战略性先导科技专项子课题(XDB42020402);国家重点基础研究发展计划(973计划)项目(2013CB429700);泰山学者工程(ts201511061)。

摘　　要：海底热液硫化物的同位素组成不仅可以示踪其来源,也记录了流体及其沉淀过程。本文分析了全球海底热液硫化物的金属(铅、铼、锇、铁、铜、锌)、非金属(硫)及其流体包裹体中的稀有气体同位素组成,探讨了硫化物中金属、非金属和稀有气体同位素组成之间的关系。结果表明:海底热液硫化物中的硫同位素组成与锇、铁同位素组成之间,铁同位素组成与铅和氦同位素组成之间,存在负相关性;其锇同位素组成与铁同位素组成之间,氙同位素组成与铅、锇同位素组成之间,则存在正相关性。在岩浆去气注入流体阶段形成的硫化物,具δ^(34)S_(VCDT)值较低(约0‰),^(3)He/^(4)He(>8 Ra)、^(40)Ar/^(36)Ar(>300)和^(129)Xe/^(132)Xe(>0.99)值较高的特点。在流体-岩石相互作用阶段,随着岩石中含铅矿物的不断溶解,即流体-岩石相互作用程度的增加,流体中沉淀的黄铁矿、黄铜矿和闪锌矿的铅质量分数增加,伴随^(206)Pb/^(204)Pb值轻微的减小。在流体-海水混合阶段,海水影响的加剧可使硫化物中的锇质量分数(约0×10^(-9))急剧降低,δ^(57)Fe值(<—1.6‰)、187 Os/188 Os值(>1)明显增大;随着流体-海水混合作用的增强,硫化物中黄铁矿的δ^(34)S_(VCDT)值将随着其流体包裹体中^(3)He/^(4)He、^(40)Ar/^(36)Ar、^(129)Xe/^(132)Xe值轻微降低而升高,而其^(3)He/^(4)He值随着其^(130)Xe/^(132)Xe值的降低而降低。以上表明,通过综合分析海底硫化物中金属、非金属和稀有气体的同位素组成和其质量分数,并讨论它们之间的关系,可以揭示岩浆去气、流体-岩石相互作用和流体-海水混合对海底热液循环的影响,进而了解硫化物沉淀过程中流体-岩石相互作用和流体-海水混合的程度。The isotopic composition of seafloor hydrothermal sulfides can not only trace their sources but also record the fluids and their precipitation processes.This article analyzes the isotopic compositions of metals(lead,rhenium,osmium,iron,copper,zinc),non-metal(sulfur),and rare gases in fluid inclusions of global seafloor hydrothermal sulfides,and explores the relationship between the isotopic compositions of metals,non-metal,and rare gases in sulfides.The results indicate that there is a negative correlation between sulfur isotopic composition and osmium,iron isotopic compositions,as well as between iron,lead,and helium isotopic compositions in seafloor hydrothermal sulfides.There is a positive correlation between osmium isotopic composition and iron isotopic composition,and between xenon isotopic composition and lead,osmium isotopic compositions.During the stage of magma degassing and material injecting fluid,sulfides are formed with the characteristics of lowδ^(34)S_(VCDT)values(about 0‰)and high^(3)He/^(4)He(>8 Ra),^(40)Ar/^(36)Ar(>300),and^(129)Xe/^(132)Xe(>0.99)ratios.In the stage of fluid-rock interaction,as lead-containing minerals in the rock continue to dissolve,i.e.,the degree of fluid-rock interaction increases,the lead content of pyrite,chalcopyrite,and sphalerite precipitated in the fluid increases,accompanied by a slight decrease in the^(206)Pb/^(204)Pb ratios.In the fluid-seawater mixing stage,with the increase of seawater influence degree,the Os content(about 0×10^(-9))in sulfides can sharply decreased,and theδ^(57)Fe value(<-1.6‰),the 187 Os/188 Os ratio(>1)significantly increases;With the enhancement of fluid-seawater mixing degree,theδ^(34)S_(VCDT)values of pyrite in sulfides will increase with a slight decrease in the^(3)He/^(4)He,^(40)Ar/^(36)Ar,and^(129)Xe/^(132)Xe ratios in its fluid inclusions,while their^(3)He/^(4)He ratios will decrease with a decrease in its^(130)Xe/^(132)Xe ratios.The above indicates that by comprehensively analyzing the isotopic composition and content of metals

关 键 词：金属、非金属和稀有气体同位素 同位素组成之间的关系 海底热液硫化物 

分 类 号：P736.4[天文地球—海洋地质] P597[天文地球—海洋科学]